a small quantity of anything thrown into or mixed with something else:

a dash of salt.

12.

a hasty or sudden movement; a rush or sudden onset:

They all made a dash for the door.

13.

the mark or sign (—) used to note an abrupt break or pause in a sentence or hesitation in an utterance, to begin and end a parenthetic word, phrase, or clause, to indicate the omission of letters or words, to divide a line, to substitute for certain uses of the colon, and to separate any of various elements of a sentence or series of sentences, as a question from its answer.

dash definition

A punctuation mark (—) used to indicate a sudden break in thought, to set off parenthetical material, or to take the place of such expressions as that is and namely: “He's running for reelection — if he lives until then”; “Very few people in this class — three, to be exact — have completed their projects”; “She joined the chorus for only one reason — she loves to sing.” In the last example, where the parenthetical material comes at the end of the sentence rather than in the middle, a colon could be used instead of the dash.